Encyclopedia
Jump to navigation
Jump to search
![](http://s9.addthis.com/button1-share.gif)
An encyclopedia (or, the less-frequently used encyclopaedia) is a book, a collection of books, or electronic media, that contains comprehensive information regarding all human knowledge or in a particular field, and is used for reference purposes. Famous encyclopedias include Encyclopaedia Britannica, Encyclopedia Americana, Catholic Encyclopedia, Wikipedia and Citizendium.